Q.
The length of latus rectum of the conic passing through the origin and having the property that normal at each point (x, y) intersects the x-axis at x+1,0 is:
see full answer
Start JEE / NEET / Foundation preparation at rupees 99/day !!
21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya
a
1
b
2
c
4
d
none of these
answer is B.
(Unlock A.I Detailed Solution for FREE)
Ready to Test Your Skills?
Check your Performance Today with our Free Mock Test used by Toppers!
Take Free Test
Detailed Solution
Let px,y be any point on the conic. ∴ slope of normal l=−dxdyEquation of normal to conic at px,y is Y−y=−dxdyX−x⇒−y=−dxdyX−x (on x-axis Y = 0)⇒X=x+ydydx Given X=x+1 ⇒ ydydx=1ydy=dx⇒y22=x+C.......i Since the conic passes through origin, x = 0, y = 0 in (i) we get C = 0∴ From (i) y2=2x Which is parabola having length of latus rectum = 4a=2units
Watch 3-min video & get full concept clarity